workstation webstart/webview unable to connect to Introscope Enterprise Manager (MOM)

Document ID : KB000004076
Last Modified Date : 14/02/2018
Show Technical Document Details
Issue:

We observe the following behavior when the Introscope Enterprise Manager (MOM) has this problem:

Not allowing any workstation client to connect to Introscope Enterprise Manager MOM.

Not allowing any Webstart to connect to Introscope Enterprise Manager MOM.

Not allowing any Webview to connect to Introscope Enterprise Manager MOM.

However, we can connect to Introscope Enterprise Manager (collectors) successfully.

We also see following error in the IntroscopeEnterpriseManager.log around the time this problem occurs:

[ERROR] [Dispatcher 1] [Manager.Dispatcher] Dispatcher 1 Unexpected exception java.nio.channels.CancelledKeyException

Environment:
Enterprise Manager 9.1 cluster, particularly prior to 9.1.5 but similar behaviour can be seen in even more recent releases, just without the particular error
Cause:

Issue with NIO implementation in Enterprise Manager, there is no negative impact to disabling this property

Resolution:
  1. As a workaround, do the following:


    Add following property in the <EM-HOME>/config/IntroscopeEnterpriseManager.properties

    transport.enable.nio=false

    Recycle the Introscope Enterprise Manager on MOM.
  2. The error has been fixed in Introscope/APM release 9.1.5.0
Additional Information:

Disabling NIO can still be a useful option if you are seeing problems with Workstation / WebView connection in more recent releases.